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Title: Experimental demonstration of coherent electron cooling of hadrons
Plain: In coherent electron cooling each ion imprints a density ripple on a co-moving electron beam, the ripple is amplified, and it then pushes the ion back toward the ideal energy; this has not yet been seen to cool a beam.
Precise: In coherent electron cooling (CeC) or its microbunched variant (MBEC), hadrons modulate the density of a co-moving electron beam, the modulation is amplified (FEL or plasma-cascade amplifier) and its field acts back on the same hadrons. Determine experimentally whether such a section produces a measurable reduction of hadron energy spread or emittance, with a cooling rate within a factor 2 of theory.
Settled by: A measured reduction of hadron bunch length, energy spread or emittance that switches off when the electron beam or amplifier is detuned.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: open
Status note: Proof-of-principle work at the BNL RHIC ring reported amplifier, beam-dynamics and diagnostic results; conference and journal records checked through mid-2026 report no observed cooling of hadrons.
Posed since: 2009